An E&E Special Report

TECHNOLOGY:

Are batteries the key to electric cars and a more responsive grid?

The Obama administration is betting that some of its stimulus grants for batteries will have a double whammy -- helping electric cars as well as the electric grid.

Yesterday, the president gave remarks at ZBB Energy Corp., a company northwest of Milwaukee. ZBB builds large batteries that can cushion the grid when there's a power hiccup -- and, it is hoped, that can eventually smooth out the electricity generated from the fickle forces of wind and sun.

But just before President Obama praised ZBB for exporting its batteries around the world, he mentioned a statistic: that in a matter of years, American firms will have gone from supplying 2 percent of the world's batteries for vehicles to 40 percent.

Experts say there are some commonalities between vehicle and grid batteries, but it's not a perfect overlap.

The American Recovery and Reinvestment Act gave billions in grants to set up manufacturing of lithium-ion batteries in the United States. These are the batteries thought to have the best near-term potential for use in vehicles -- they're relatively light and carry plenty of energy. Nissan, General Motors, Ford and Toyota are among the companies planning to use the batteries in plug-in cars.

Some companies receiving the auto-battery grants will also be working on grid batteries. A123Systems and Ener1, for example, each make lithium-ion batteries for cars; together, they received more than $350 million in grants for auto batteries, and both have recently announced demonstration projects for storing power from the grid.

A potential market for used electric car batteries

In June, Ener1 announced a project in Russia to install batteries that serve remote parts of the grid as well as surging demand in the cities. The batteries aren't fundamentally different, though, from those used in cars -- they are merely of a larger scale.

Ener1 has said that in the longer term, it sees a lucrative market in collecting the used lithium-ion batteries from electric cars, then stringing many together to build a grid-scale battery.

Can it work?

Gary Yang, laboratory fellow and leader of stationary storage at the Pacific Northwest National Laboratory, said this is a "good approach, good idea, but the technology might not be there for both purposes."

Every used car battery has some wrinkles from its experience. During its warranty period, a driver may regularly stress it with 15-minute quick charges, or she may drive with a lead foot, or she may live in a hundred-degree climate.

Yang said he's unsure that a lithium-ion battery that has gone through all this could still store energy from the grid. "It's still questionable after warranty time if it's a useful technology for this purpose," he said.

But lithium-ion batteries are only one of a half-dozen options to store power from the grid. Another option is a "flow" battery, like ZBB's, which uses different materials and is built differently.

The zinc-bromide battery uses materials that are more common and cheaper than lithium, and the different construction means it can last longer. Researchers see it as a cheap, high-power option compared to lithium-ion, which is smaller and more expensive.

Batteries may help utilities handle more renewables

But so few utilities are buying energy storage, Yang said, that the price of these batteries has yet to decline.

Obama has directed some policies at that problem. ZBB, for example, has received tax credits and grants that will allow it to triple production. In November, the Department of Energy awarded $185 million for grid-scale energy storage projects, including batteries.

The most established technologies are pumped hydropower and compressed air, but each of these is geography-dependent. Battery and other forms of storage, it is thought, would help establish solar and wind more widely, not just where hydro and compressed air allow.

Yang said batteries aren't the "silver bullet," either; every region will, theoretically, have a different energy storage technology for its needs.

Some areas, for example, have lots of server farms or commercial users that need a flawless, constant stream of power; batteries or flywheels might suit, because they can offer quick jolts that smooth out the bumps in the grid.

Other regions may have installed several gigawatts of wind power; when the breeze kicks in, flywheels won't do. Instead, a bundle of high-capacity batteries could handle the load, or a hydro pump.

Nevertheless, Yang said, batteries like ZBB's have a long way to go before they'll be accepted by utilities. In particular, he said the batteries have to last through more charges and require less maintenance.